Chromosoma最新文献

{"title":"A large-scale RNAi screen reveals that mitochondrial function is important for meiotic chromosome organization in oocytes.","authors":"Karen Jule Nieken,&nbsp;Kathryn O'Brien,&nbsp;Alexander McDonnell,&nbsp;Liudmila Zhaunova,&nbsp;Hiroyuki Ohkura","doi":"10.1007/s00412-023-00784-9","DOIUrl":"https://doi.org/10.1007/s00412-023-00784-9","url":null,"abstract":"<p><p>In prophase of the first meiotic division, chromatin forms a compact spherical cluster called the karyosome within the enlarged oocyte nucleus in Drosophila melanogaster. Similar clustering of chromatin has been widely observed in oocytes in many species including humans. It was previously shown that the proper karyosome formation is required for faithful chromosome segregation, but knowledge about its formation and maintenance is limited. To identify genes involved in karyosome formation, we carried out a large-scale cytological screen using Drosophila melanogaster oocytes. This screen comprised 3916 genes expressed in ovaries, of which 106 genes triggered reproducible karyosome defects upon knockdown. The karyosome defects in 24 out of these 106 genes resulted from activation of the meiotic recombination checkpoint, suggesting possible roles in DNA repair or piRNA processing. The other genes identified in this screen include genes with functions linked to chromatin, nuclear envelope, and actin. We also found that silencing of genes with mitochondrial functions, including electron transport chain components, induced a distinct karyosome defect typically with de-clustered chromosomes located close to the nuclear envelope. Furthermore, mitochondrial dysfunction not only impairs karyosome formation and maintenance, but also delays synaptonemal complex disassembly in cells not destined to become the oocyte. These karyosome defects do not appear to be mediated by apoptosis. This large-scale unbiased study uncovered a set of genes required for karyosome formation and revealed a new link between mitochondrial dysfunction and chromatin organization in oocytes.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"132 1","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9981535/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10145961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Super-resolution microscopy reveals the number and distribution of topoisomerase IIα and CENH3 molecules within barley metaphase chromosomes.","authors":"Ivona Kubalová,&nbsp;Klaus Weisshart,&nbsp;Andreas Houben,&nbsp;Veit Schubert","doi":"10.1007/s00412-023-00785-8","DOIUrl":"https://doi.org/10.1007/s00412-023-00785-8","url":null,"abstract":"<p><p>Topoisomerase IIα (Topo IIα) and the centromere-specific histone H3 variant CENH3 are key proteins involved in chromatin condensation and centromere determination, respectively. Consequently, they are required for proper chromosome segregation during cell divisions. We combined two super-resolution techniques, structured illumination microscopy (SIM) to co-localize Topo IIα and CENH3, and photoactivated localization microscopy (PALM) to determine their molecule numbers in barley metaphase chromosomes. We detected a dispersed Topo IIα distribution along chromosome arms but an accumulation at centromeres, telomeres, and nucleolus-organizing regions. With a precision of 10-50 nm, we counted ~ 20,000-40,000 Topo IIα molecules per chromosome, 28% of them within the (peri)centromere. With similar precision, we identified ~13,500 CENH3 molecules per centromere where Topo IIα proteins and CENH3-containing chromatin intermingle. In short, we demonstrate PALM as a useful method to count and localize single molecules with high precision within chromosomes. The ultrastructural distribution and the detected amount of Topo IIα and CENH3 are instrumental for a better understanding of their functions during chromatin condensation and centromere determination.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"132 1","pages":"19-29"},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9981516/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9360421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex-chrom v. 2.0: a database of green plant species with sex chromosomes.","authors":"Sònia Garcia,&nbsp;Bohuslav Janousek,&nbsp;Joan Pere Pascual-Díaz,&nbsp;Susanne S Renner","doi":"10.1007/s00412-023-00786-7","DOIUrl":"https://doi.org/10.1007/s00412-023-00786-7","url":null,"abstract":"","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"132 1","pages":"55-58"},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9364612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytogenetic status of patients with congenital malformations or suspected chromosomal abnormalities in Turkey: a comprehensive cytogenetic survey of 11,420 patients.","authors":"Osman Demirhan,&nbsp;Erdal Tunç","doi":"10.1007/s00412-022-00782-3","DOIUrl":"https://doi.org/10.1007/s00412-022-00782-3","url":null,"abstract":"<p><p>Cytogenetic analysis is helpful in diagnostic workup of patients having prenatal or early postnatal medical problems and provides a basis for genetic counseling or deciding on clinical treatment options. Chromosomal abnormalities (CAs) constitute one of the most important category of genetic defects which have the potential to cause irreversible disorders. In this study, chromosome analysis results of 11,420 patients having congenital malformations or suspected of having chromosomal abnormalities, who were referred to Çukurova University Research and Training Hospital Cytogenetic Laboratory over a 16-year period, were investigated, retrospectively. Of all patients analyzed, CAs were found in 1768 cases, accounting for 15.5% of all cases. It was observed that 1175 (15.5%) of CAs were numerical (10.3%) and 593 (5.2%) were structural chromosome abnormalities. Among numerical CAs, Down syndrome (DS), Turner syndrome (TS) and Klinefelter syndrome (KS) constituted common categories which were observed in 7, 1.1 and 0.9% of all cases, respectively. Among the structural CAs, translocations, inversions, fragilities, deletions,, and others were the most common categories and constituted 2.2, 0.9, 0.9, 0.7, 0.3, and 0.3% of all cases, respectively. The sex ratio (male/female) of all cases was 1.01 and of DS cases was 1.6. Our results further confirmed that cytogenetic analysis is necessary in terms of making definite diagnosis of genetic disorders, providing proper genetic counseling and clinical treatment, assessing the recurrence risk, and preventing the hereditary genetic diseases and disorders. Besides, such studies will greatly assist in constituting national and international databases or records of genetic disorders.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 4","pages":"225-237"},"PeriodicalIF":1.6,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33500097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of the somatic TADs and lampbrush chromomere-loop complexes in transcriptionally active prophase I oocytes.","authors":"Tatiana Kulikova,&nbsp;Antonina Maslova,&nbsp;Polina Starshova,&nbsp;Juan Sebastian Rodriguez Ramos,&nbsp;Alla Krasikova","doi":"10.1007/s00412-022-00780-5","DOIUrl":"https://doi.org/10.1007/s00412-022-00780-5","url":null,"abstract":"<p><p>In diplotene oocyte nuclei of all vertebrate species, except mammals, chromosomes lack interchromosomal contacts and chromatin is linearly compartmentalized into distinct chromomere-loop complexes forming lampbrush chromosomes. However, the mechanisms underlying the formation of chromomere-loop complexes remain unexplored. Here we aimed to compare somatic topologically associating domains (TADs), recently identified in chicken embryonic fibroblasts, with chromomere-loop complexes in lampbrush meiotic chromosomes. By measuring 3D-distances and colocalization between linear equidistantly located genomic loci, positioned within one TAD or separated by a TAD border, we confirmed the presence of predicted TADs in chicken embryonic fibroblast nuclei. Using three-colored FISH with BAC probes, we mapped equidistant genomic regions included in several sequential somatic TADs on isolated chicken lampbrush chromosomes. Eight genomic regions, each comprising two or three somatic TADs, were mapped to non-overlapping neighboring lampbrush chromatin domains - lateral loops, chromomeres, or chromomere-loop complexes. Genomic loci from the neighboring somatic TADs could localize in one lampbrush chromomere-loop complex, while genomic loci belonging to the same somatic TAD could be localized in neighboring lampbrush chromomere-loop domains. In addition, FISH-mapping of BAC probes to the nascent transcripts on the lateral loops indicates transcription of at least 17 protein-coding genes and 2 non-coding RNA genes during the lampbrush stage of chicken oogenesis, including genes involved in oocyte maturation and early embryo development.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 4","pages":"207-223"},"PeriodicalIF":1.6,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33441560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A step forward in the genome characterization of the sugarcane borer, Diatraea saccharalis: karyotype analysis, sex chromosome system and repetitive DNAs through a cytogenomic approach.","authors":"Ana E Gasparotto,&nbsp;Diogo Milani,&nbsp;Emiliano Martí,&nbsp;Ana Beatriz S M Ferretti,&nbsp;Vanessa B Bardella,&nbsp;Frederico Hickmann,&nbsp;Magda Zrzavá,&nbsp;František Marec,&nbsp;Diogo C Cabral-de-Mello","doi":"10.1007/s00412-022-00781-4","DOIUrl":"https://doi.org/10.1007/s00412-022-00781-4","url":null,"abstract":"<p><p>Moths of the family Crambidae include a number of pests that cause economic losses to agricultural crops. Despite their economic importance, little is known about their genome architecture and chromosome evolution. Here, we characterized the chromosomes and repetitive DNA of the sugarcane borer Diatraea saccharalis using a combination of low-pass genome sequencing, bioinformatics, and cytogenetic methods, focusing on the sex chromosomes. Diploid chromosome numbers differed between the sexes, i.e., 2n = 33 in females and 2n = 34 in males. This difference was caused by the occurrence of a WZ₁Z₂ trivalent in female meiosis, indicating a multiple sex-chromosome system WZ₁Z₂/Z₁Z₁Z₂Z₂. A strong interstitial telomeric signal was observed on the W chromosome, indicating a fusion of the ancestral W chromosome with an autosome. Among repetitive DNAs, transposable elements (TEs) accounted for 39.18% (males) to 41.35% (females), while satDNAs accounted for only 0.214% (males) and 0.215% (females) of the genome. FISH mapping revealed different chromosomal organization of satDNAs, such as single localized clusters, spread repeats, and non-clustered repeats. Two TEs mapped by FISH were scattered. Although we found a slight enrichment of some satDNAs in the female genome, they were not differentially enriched on the W chromosome. However, we found enriched FISH signals for TEs on the W chromosome, suggesting their involvement in W chromosome degeneration and differentiation. These data shed light on karyotype and repetitive DNA dynamics due to multiple chromosome fusions in D. saccharalis, contribute to the understanding of genome structure in Lepidoptera and are important for future genomic studies.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 4","pages":"253-267"},"PeriodicalIF":1.6,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33500098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life of double minutes: generation, maintenance, and elimination.","authors":"Mila Ilić, Irene C Zaalberg, Jonne A Raaijmakers, René H Medema","doi":"10.1007/s00412-022-00773-4","DOIUrl":"10.1007/s00412-022-00773-4","url":null,"abstract":"<p><p>Advances in genome sequencing have revealed a type of extrachromosomal DNA, historically named double minutes (also referred to as ecDNA), to be common in a wide range of cancer types, but not in healthy tissues. These cancer-associated circular DNA molecules contain one or a few genes that are amplified when double minutes accumulate. Double minutes harbor oncogenes or drug resistance genes that contribute to tumor aggressiveness through copy number amplification in combination with favorable epigenetic properties. Unequal distribution of double minutes over daughter cells contributes to intratumoral heterogeneity, thereby increasing tumor adaptability. In this review, we discuss various models delineating the mechanism of generation of double minutes. Furthermore, we highlight how double minutes are maintained, how they evolve, and discuss possible mechanisms driving their elimination.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 1","pages":"107-125"},"PeriodicalIF":2.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9470669/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48307019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NucPosDB: a database of nucleosome positioning in vivo and nucleosomics of cell-free DNA.","authors":"Mariya Shtumpf,&nbsp;Kristan V Piroeva,&nbsp;Shivam P Agrawal,&nbsp;Divya R Jacob,&nbsp;Vladimir B Teif","doi":"10.1007/s00412-021-00766-9","DOIUrl":"https://doi.org/10.1007/s00412-021-00766-9","url":null,"abstract":"<p><p>Nucleosome positioning is involved in many gene regulatory processes happening in the cell, and it may change as cells differentiate or respond to the changing microenvironment in a healthy or diseased organism. One important implication of nucleosome positioning in clinical epigenetics is its use in the \"nucleosomics\" analysis of cell-free DNA (cfDNA) for the purpose of patient diagnostics in liquid biopsies. The rationale for this is that the apoptotic nucleases that digest chromatin of the dying cells mostly cut DNA between nucleosomes. Thus, the short pieces of DNA in body fluids reflect the positions of nucleosomes in the cells of origin. Here, we report a systematic nucleosomics database - NucPosDB - curating published nucleosome positioning datasets in vivo as well as datasets of sequenced cell-free DNA (cfDNA) that reflect nucleosome positioning in situ in the cells of origin. Users can select subsets of the database by a number of criteria and then obtain raw or processed data. NucPosDB also reports the originally determined regions with stable nucleosome occupancy across several individuals with a given condition. An additional section provides a catalogue of computational tools for the analysis of nucleosome positioning or cfDNA experiments and theoretical algorithms for the prediction of nucleosome positioning preferences from DNA sequence. We provide an overview of the field, describe the structure of the database in this context, and demonstrate data variability using examples of different medical conditions. NucPosDB is useful both for the analysis of fundamental gene regulation processes and the training of computational models for patient diagnostics based on cfDNA. The database currently curates ~ 400 publications on nucleosome positioning in cell lines and in situ as well as cfDNA from > 10,000 patients and healthy volunteers. For open-access cfDNA datasets as well as key MNase-seq datasets in human cells, NucPosDB allows downloading processed mapped data in addition to the regions with stable nucleosome occupancy. NucPosDB is available at https://generegulation.org/nucposdb/ .</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 1-2","pages":"19-28"},"PeriodicalIF":1.6,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8776978/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9236121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incorporation of CENP-A/CID into centromeres during early Drosophila embryogenesis does not require RNA polymerase II-mediated transcription.","authors":"Samadri Ghosh,&nbsp;Christian F Lehner","doi":"10.1007/s00412-022-00767-2","DOIUrl":"https://doi.org/10.1007/s00412-022-00767-2","url":null,"abstract":"<p><p>In many species, centromere identity is specified epigenetically by special nucleosomes containing a centromere-specific histone H3 variant, designated as CENP-A in humans and CID in Drosophila melanogaster. After partitioning of centromere-specific nucleosomes onto newly replicated sister centromeres, loading of additional CENP-A/CID into centromeric chromatin is required for centromere maintenance in proliferating cells. Analyses with cultured cells have indicated that transcription of centromeric DNA by RNA polymerase II is required for deposition of new CID into centromere chromatin. However, a dependence of centromeric CID loading on transcription is difficult to reconcile with the notion that the initial embryonic stages appear to proceed in the absence of transcription in Drosophila, as also in many other animal species. To address the role of RNA polymerase II-mediated transcription for CID loading in early Drosophila embryos, we have quantified the effects of alpha-amanitin and triptolide on centromeric CID-EGFP levels. Our analyses demonstrate that microinjection of these two potent inhibitors of RNA polymerase II-mediated transcription has at most a marginal effect on centromeric CID deposition during progression through the early embryonic cleavage cycles. Thus, we conclude that at least during early Drosophila embryogenesis, incorporation of CID into centromeres does not depend on RNA polymerase II-mediated transcription.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 1-2","pages":"1-17"},"PeriodicalIF":1.6,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9079035/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9236108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple heterochromatin diversification events in the genome of fungus-farming ants: insights from repetitive sequences.","authors":"Gisele Amaro Teixeira,&nbsp;Luísa Antônia Campos Barros,&nbsp;Hilton Jeferson Alves Cardoso de Aguiar,&nbsp;Denilce Meneses Lopes","doi":"10.1007/s00412-022-00770-7","DOIUrl":"https://doi.org/10.1007/s00412-022-00770-7","url":null,"abstract":"<p><p>A substantial portion of the eukaryotic genome includes repetitive DNA, which is important for its stability, regulation, and architecture. Fungus-farming ant genomes show remarkable structural rearrangement rates that were necessary for the establishment of their agriculture-based lifestyle, highlighting the relevance of this peculiar group in understanding the repetitive portion of ant genome. Chromosomal banding studies are in accordance with genomic data because they show that repetitive heterochromatic sequences of basal and derivative Attina species are GC-rich, an uncommon trait in Formicidae. To understand the evolutionary dynamics of heterochromatin in Attina, we compared GC-rich heterochromatin patterns between the Paleoattina and Neoattina clades of this subtribe. To this end, we hybridized the Mrel-C₀t probe (highly and moderately repetitive DNA) obtained from Mycetomoellerius relictus, Neoattina with GC-rich heterochromatin, in karyotypes of Paleoattina and Neoattina species. Additionally, we mapped the repetitive sequences (GA)₁₅ and (TTAGG)₆ in species of the two clades to investigate their organization and evolutionary patterns in the genome of Attina. The Mrel-C₀t probe marked the heterochromatin in M. relictus, in other Mycetomoellerius spp., and in species of Mycetarotes, Cyphomyrmex, and Sericomyrmex (Neoattina). In Mycetomoellerius urichii, only pericentromeric heterochromatin was marked with Mrel-C₀t. No marking was observed in Paleoattina species or in Atta and Acromyrmex (Neoattina). These results indicated that different evolutionary events led to heterochromatin differentiation in Attina. The most likely hypothesis is that GC-rich heterochromatin arose in the common ancestor of the two clades and accumulated various changes throughout evolution. The sequences (GA)₁₅ and (TTAGG)₆ located in euchromatin and telomeres, respectively, showed more homogeneous results among the species.</p>","PeriodicalId":10248,"journal":{"name":"Chromosoma","volume":"131 1-2","pages":"59-75"},"PeriodicalIF":1.6,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9284806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}